The general concept of using the electrical conductivity of a projectile to track “hits” on a target is well known within the art. The basic premise is that a projectile made of metal or other conductive material passes through two conductive and electrically isolated layers of a target and completes a circuit. This electrical signal is then passed from the target to another apparatus in order to track the hit.
Much of the prior art is focused on design and construction of the target itself, rather than system features required to operate the targets and track hits. For example, U.S. Pat. No. 4,828,269, issued May 9, 1989, shows a hit-scoring target for shooting practice having several mutually bonded layers. A first layer, at least the outside surface of which is electrically conductive, a second, electrically nonconductive and at least semi-rigid layer imparting mechanical strength to the first layer and made of a material tolerant of the heat of a freshly fired projectile, a third, electrically nonconductive layer made of an elastically resilient material, a fourth layer of which at least the surface contacting the third layer is electrically conductive, and a fifth layer serving as a backing and imparting relative rigidity to the target. The distance between the electrically conductive surfaces of the first and the fourth layer is smaller than the length of the shortest projectile to be fired at the target, whereby a projectile hitting, penetrating, and passing through the target causes a transient electrical low-resistance connection to be established between the electrically conductive surfaces.
U.S. Pat. No. 4,240,640, issued Dec. 23, 1980, shows an electrical, projectile penetration-sensing target made of a pair of laminated sheets including a polymer resin coated brittle, calendered aluminum wire screen, and a polymer resin coated, fiberglass web. The laminated sheets are separated by and bonded to a sheet of small celled foamed polypropylene. The wire screens are electrically connected to a resistance responsive network whose output is a relatively wide pulse, which is coupled to a recording device.
U.S. Pat. No. 3,854,722, issued Dec. 17, 1974, shows a target with pairs of penetrable, electrical-conductive sheet-like elements that are flatwise opposed and spaced apart a distance to be transiently electrically connected by a penetrating projectile. Each pair corresponds to an annular scoring zone. Elements for radially outer scoring zones are on a permanent front sheet-like structure; those for inner ones are on a readily replaceable sheet-like structure installed behind the front one. To accommodate possible misalignment of the sheet-like structures, the radially innermost elements on the front structure partially radially overlap the radially outermost ones on the rear one. Such overlapping elements cooperate for one scoring zone, and corresponding ones of them on the two structures are electrically interconnected.
Other target systems have focused on target holding devices. For example, U.S. Pat. No. 6,994,347, issued Feb. 7, 2006, provides a hit-scoring apparatus for shooting practice, comprising a target holder with a body constituting the first and second jaws of a clamping device. The first jaw and the second jaw are electrically insulated from one another, with means adapted to produce a relative movement between the first jaw and the second jaw. A target panel is clampable between the first and second jaws. The target panel has a plurality of layers, including an electrically conductive front layer and an electrically conductive second layer separated and spaced apart from the front layer by at least one electrically non-conductive layer. When the target panel is clamped between the first and second jaws of the target holder, separate electrical contacts are established between the front layer and the first jaw on the one hand, and between the second layer and the second jaw on the other hand. The first and second jaws are connectable to a hit-scoring unit.
U.S. Pat. No. 8,047,546, issued Nov. 1, 2011, shows a target holder assembly for interchangeably supporting a two-dimensional target and a three-dimensional target. It includes an enclosure and a target holder frame connected to the enclosure. The target holder frame has a cross arm member connected between two target arms. The cross arm has a base length with clamping members extending from both ends of the base length to engage three dimensional targets. The cross arm also has receiving grooves proximate the junction of the clamping members and the base length positioned to engage the two-dimensional targets. A front protrusion is positioned along the base length to engage either the two-dimensional target or the three-dimensional target. The holder assembly further includes a clamping apparatus connected to the base length to engage either the two-dimensional target or the three-dimensional target.
Known hit-sensing target systems are deficient for various reasons, including inadequate target durability, excessively high costs per target, inability to be easily serviced by users in the field, lack of portability, lack of ability to adequately track shooting performance, and lack of ability to control target positioning during a shooting event, for example. Accordingly, there is a need for improvements to known target systems to address these and other deficiencies.